1. B260: Fundamentals of Nursing Practice
Gas Exchange
Vema Sweitzer, MN, RN

2. Gas exchange/Oxygenation
Oxygenation can be defined as the mechanisms that facilitate or impair the body’s ability to supply oxygen to all cells of the body. The function of the respiratory system is to obtain oxygen from atmospheric air, to transport this air through the respiratory tract into the alveoli, and ultimately to diffuse oxygen into the body that carries oxygen to all the cells of the body.

3. Pulmonary System Ventilation Perfusion
The process of moving gases into and out of the lungs
Perfusion
The ability of the cardiovascular system to pump oxygenated blood to the tissues and return deoxygenated blood to the lungs

4. Pulmonary System
Diffusion: Exchange of respiratory gases in the alveoli and capillaries.
The thickness of the alveolar capillary membrane affects the rate of diffusion.
Oxygen transport = Lungs + cardiovascular (CV) system
Hemoglobin carries O2 and CO2
Carbon dioxide transport

5. Pulmonary System
Three things influence the capacity of the blood to carry O2:
The amount of dissolved O2 in the plasma
The amount of hemoglobin
the tendency of hemoglobin to bind with O2
The primary function of the lungs is to transfer oxygen from the atmosphere into the alveoli and carbon dioxide out of the body as a waste product.
The airways of the lung transfer oxygen from the atmosphere to the alveoli, where the oxygen is exchanged for carbon dioxide.
Through the alveolar capillary membrane, oxygen transfers to the blood, and carbon dioxide transfers from the blood to the alveoli.
Conditions and diseases that change the structure and function of the pulmonary system alter respiration.
The respiratory muscles, pleural space, lungs, and alveoli are essential for ventilation, perfusion, and exchange of respiratory gases.
Gases move into and out of the lungs through pressure changes. Intrapleural pressure is negative, or less than atmospheric pressure, which is 760 mm Hg at sea level. For air to flow into the lungs, intrapleural pressure becomes more negative, setting up a pressure gradient between the atmosphere and the alveoli.
The diaphragm and external intercostal muscles contract to create a negative pleural pressure and increase the size of the thorax for inspiration. Relaxation of the diaphragm and contraction of the internal intercostal muscles allow air to escape from the lungs.
The major inspiratory muscle of respiration is the diaphragm.
[Shown is Figure 40-1 on text p. 822.]

6. Cardiovascular Physiology
Cardiopulmonary physiology involves delivery of deoxygenated blood (blood high in carbon dioxide and low in oxygen) to the right side of the heart and then to the lungs, where it is oxygenated.
Oxygenated blood (blood high in oxygen and low in carbon dioxide) then travels from the lungs to the left side of the heart and the tissues.

7. Cardiovascular Physiology

8. Blood Flow Regulation Cardiac output (CO) =
Amount of blood ejected from the left ventricle each minute
Stroke volume
Amount of blood ejected from the left ventricle with each contraction
Cardiac output (CO) =
Stroke volume (SV) × Heart rate (HR)
Preload
End-diastolic pressure
Afterload
Resistance to left ventricular ejection

9. Factors Affecting Oxygenation
Physiological factors
Decreased oxygen-carrying
capacity
Hypovolemia
Decreased inspired oxygen concentration
Increased metabolic rate

10. Factors Affecting Oxygenation
Factors Affecting Chest Wall Movement
Pregnancy
Obesity
Musculoskeletal abnormalities
Kyphosis of the vertebral column and kyphosis
Pectus excavatum
Pectus Excavatum
Kyphosis

11. Factors Affecting Oxygenation
Factors Affecting Chest Wall Movement
Trauma
Neuromuscular disease
CNS alterations
Chronic disease

12. Alterations in Respiratory Functioning
Definition
Causes
Signs and symptoms
Hypoventilation
Hyperventilation
Hypoxia

13. Lifestyle Factors
Nutrition
Cardioprotective nutrition = Diets rich in fiber; whole grains; fresh fruits and vegetables; nuts; antioxidants; lean meats; and omega-3 fatty acids.
Exercise
People who exercise for 30 to 60 minutes daily have a lower pulse rate and blood pressure, decreased cholesterol level, increased blood flow, and greater oxygen extraction by working muscles.

14. Lifestyle Risk Factors
Smoking
Associated with heart disease, COPD, and lung cancer
The risk of lung cancer is 10 times greater for a person who smokes than for a nonsmoker.
Substance abuse
Excessive use of alcohol and other drugs impairs tissue oxygenation.
Stress
A continuous state of stress or severe anxiety increases the metabolic rate and oxygen demand of the body.

15. Environmental Factors
The incidence of pulmonary disease is higher in smoggy, urban areas than in rural areas.
A patient’s workplace sometimes increases the risk for pulmonary disease.
Coccidioidomycosis
Asbestosis

16. Hemoglobin The amount of hemoglobin is in whole blood
Adult males: 13.2 to 17.3 g/dL
Adult women: 11.7 to 15.5 g/dL
Men after middle age: 12.4 to g/dL
Women after middle age: 11.7 to g/dL

17. Hematocrit
Hematocrit is a blood test that measures the percentage of the volume of whole blood that is made up of red blood cells
Normal results vary, but in general are as follows:
Male: 39% to 50.%
Female: 36.1 to 44.3%

18. Pneumonia
Pneumonia is an acute inflammation of the lung that is most frequently caused by a microorganism.
Fluid and exudate in the alveoli.
Stareptococcus pneumoniae

19. Intervention Nasal cannula Delivers flow rate up to 6 L/min
(24% to 40% oxygen)
(Skill 40-4)

20. Methods of Oxygen Delivery
Simple Face Mask.
Delivers 40% to 60% at liter flows of 5-8 L/min
Simple Face Mask
To avoid rebreathing of CO2 by the client while wearing a mask, a minimum 5 L/min oxygen flow rate is required

21. Methods of Oxygen Delivery
A plastic face mask with a reservoir bag is capable of delivering higher concentrations of oxygen. A partial rebreather mask is a simple mask with a reservoir bag that should be at least one third to one half full on inspiration and delivers from 40% to 70% with a flow rate of 6-10 L/min
Non-Rebreather Mask
Oxygen 60% to 95%, flows into reservoir bag and mask. Valve prevents expired air from flowing back into bag.
Partial Rebreather Mask
Reservoir bag conserves oxygen concentrations of 40-60%, only difference is valve between mask and bag is removed

22. Methods of Oxygen Delivery
Venturi mask delivers higher oxygen concentrations of 24% to 60% with oxygen flow rates of 4 to 12 L/min, depending on the flow- control meter selected.
The Venturi mask can deliver oxygen concentration of 24-60% with oxygen
flow rates of 4-12 liters/minutes

23. Oxygenation Safety
Oxygen must be prescribed and adjusted only with a HCP’s order.
Determine that all electrical equipment in the room is functioning correctly and properly grounded. An electrical spark in the presence of oxygen can result in a serious fire.
Check the oxygen level of portable tanks before transporting a patient to ensure there is enough oxygen in the tank.

24. Oxygenation Safety
Secure oxygen cylinders so they do not fall over. Store them upright and either chained or secured in appropriate holders.

25. Suctioning
Suctioning is necessary when patients are unable to clear respiratory secretions from the airways by coughing or other less invasive procedures.

26. How to Suction a Tracheostomy

27. How to Suction a Tracheostomy

28. Emergency Patient is having Acute Dyspnea
Acute dyspnea for patient with tracheostomy is most commonly caused by partial or complete blockage of the tracheostomy tube retained secretions. To unblock the tracheostomy tube:
1. ASK THE PATIENT TO COUGH: A strong cough may be all that is needed to expectorate secretions.
2. REMOVE THE INNER CANNULA: If there are secretions stuck in the tube, they will automatically be removed when you take out the inner cannula. The outer tube – which does not have secretions in it – will allow the patient to breath freely. Clean and replace the inner cannula.
3. SUCTION: If coughing or removing the inner cannula do not work, it may be that secretions are lower down the patients airway. Use the suction machine to remove secretions.
4. If these measures fail – commence low concentration oxygen therapy via a tracheostomy mask, and call for medical assistance.

29. Suctioning (Skill 40-1) Key points: Use sterile procedure
Suction set on continuous suction of mm Hg
Insert catheter, suction intermittently seconds and slowly rotate and withdraw
Monitor patient:
Risk for hypoxia
Hypotension
Arrhythmias
Trauma
Irritation
Nursing Diagnosis: Ineffective airway clearance
r/t retention of secretions and poor cough effort.
Vagal stimulation:
potentially hazardous complication from suctioning, can lead to bradycardia
vagus nerve is the pneumogastric (10th cranial nerve) with motor and sensory functions, wide distribution
Signs and symptoms of Hypoxia
Apprehensive
Restlessness, inability to concentrate
↓ LOC
Dizziness
Behavioral changes
Agitated
↑ RR
↑ HR
Late signs: ↓ RR, ↓ HR and cynosis

30. Oxygenation: Chest Tubes
A catheter placed through the thorax to remove air and fluids from the pleural space
Purpose
To remove air and fluids from the pleural space
To prevent air or fluid from reentering the pleural space
To re-establish normal intra-pleural and intra- pulmonary pressures

31. Nursing Care (interventions)
Maintain secure, airtight dressing
Maintain underwater seal
Monitor and secure all connections
Observe for bubbling
Monitor tubing for patency
Record output (quantity, characteristics)
Monitor patient
Dressing changes per agency